I actually live in a town like you describe desiring. All the people here know each other once you get here and have been around a while, but there's still an in flux of new people constantly so no ones left out. As in, if I am out and about, odds are I will run into one or more people who know me personally doing routine errands. I haven't lived here all that long either. I think it may be a combination of the size and location desirability (beach). We aren't too big, aren't too small, feels just right.